JetBrains: Make browser UI style look more native

Created by: vdavid

The dropdowns are great now! But I've found some significant differences in the UI that make the browser still feel out of place compared to the native UI.

I've tried to collect the biggest things I've spotted: (The images on the left are the native ones, the ones on the right are ours)

1. Text selection color is different from the JetBrains native color:

2. Icon hover background color is different (see below)

3. Tooltip background, padding, and font size are different (see below)

4. “Copy fill query ⌘+⇧+C” is mentioned but it doesn't actually work. Let's remove this from the tooltip if we can.

5. The dark background around the search box. JetBrains doesn't use this color for anything except code editor backgrounds. I think this is the same (white) for the default light theme, but for dark themes, it's a very different shade of gray. Here:

6. Even more so for the search results:

7. Repo star count and line number text is significantly smaller than it is in the native window (native is 13px, ours is 0.625rem which is 10px)